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How many gallons is my pool?

How Many Gallons Is My Pool?

Find your size in the tables, or answer three questions for an exact number.

1 of 3

What shape is your pool?

Your gallons appear here after step 3.

about 6,700: gallons in an 18 ft x 48 in above-ground pool
about 17,200: gallons in a 16 x 32 ft inground pool
660,000: gallons in an Olympic pool

To work out how many gallons your pool holds, you need three numbers: how long it is, how wide it is, and how deep it is on average. Picture a typical backyard inground pool at 16 x 32 ft, holding water to around 4.5 feet deep. That one holds roughly 17,200 gallons. Why does the number matter? Because every chemical dose depends on it, and the site's dose calculators remember your gallons in your browser and fill them in for you.

Inground pool gallons: 12x24, 16x32, 20x40

All of these assume the water averages 4.5 feet deep. If your pool is deeper than that, it holds more, so treat these numbers as a starting point.

Pool (ft), 4.5 ft average depth	Gallons	Liters
12 x 24	9,690	36,700
14 x 28	13,200	50,000
16 x 32	17,240	65,200
18 x 36	21,810	82,600
20 x 40	26,930	101,900

Above-ground pool gallons by size

Above-ground pool	Water depth	Gallons	Liters
12 ft x 30 in	24 in	1,690	6,400
12 ft x 48 in	42 in	2,960	11,200
15 ft x 48 in	42 in	4,630	17,500
16 ft x 48 in	42 in	5,260	19,900
18 ft x 48 in	42 in	6,660	25,200
18 ft x 52 in	46 in	7,300	27,600
21 ft x 52 in	46 in	9,930	37,600
24 ft x 52 in	46 in	12,970	49,100

Oval above-ground pool gallons

Oval above-ground pool	Water depth	Gallons	Liters
12 x 24 ft x 52 in	46 in	6,490	24,600
15 x 30 ft x 52 in	46 in	10,130	38,400
16 x 32 ft x 52 in	46 in	11,530	43,600
18 x 33 ft x 52 in	46 in	13,380	50,600
18 x 40 ft x 54 in	48 in	16,920	64,100

How to work out your pool's gallons

Measure the water's length, width, and depth to estimate its volume. One thing to watch: measure the water, not the deck around it.

1. Start with the water's dimensions: how far it stretches lengthwise and widthwise, in feet. For a round pool, run the tape straight across the center.
2. Check the depth at both ends, shallow and deep.
3. Work out the average depth. That is the number halfway between your two readings. So a pool with a 3 foot shallow end and a 6 foot deep end averages 4.5 feet.
4. For a rectangular pool, multiply length by width by average depth, and that result by 7.48 to get US gallons.

A round or oval pool holds less water than a rectangle of the same length and width. For those shapes, multiply by 5.9 in place of 7.48.

How many gallons in an Olympic pool?

Olympic pools measure 50 meters by 25 meters, with a depth of 2 meters. In US terms, that is roughly 660,000 gallons, about 2.5 million liters of water.

That is many times the water in a 16 x 32 ft backyard pool.

Common questions

How much water is in a 16 x 32 ft pool with a deep end?

Say the floor slopes from 3 feet at one end to 6 feet at the other. Add them (3 + 6 = 9) and halve it: the average depth is 4.5 feet, so a 16 x 32 ft pool holds about 17,200 gallons. A deeper floor means more water than that.

How much water does an 18 ft x 48 in pool hold?

For an 18 ft round pool with water about 42 inches deep (3.5 ft, half a foot below the top of the 48 inch wall), multiply 18 x 18 x 3.5 x 5.9, which comes to about 6,700 gallons. The result is the pool's volume in US gallons. If the water is lower than the wall, use the water's depth.

How long does it take to fill a 5,000 gallon pool?

Your hose sets the pace. If a 5-gallon bucket under your hose takes 40 seconds to fill, the hose is moving 7.5 gallons a minute. At that speed, 5,000 gallons takes about 11 hours. The fill calculator can work it out for your own hose. Just tell it how many seconds the bucket took. Keep in mind that water bills charge per 1,000 gallons and often tack on sewer fees too.